Heterocyclic ketone and thioester compounds and uses

ABSTRACT

This invention relates to neurotrophic, low molecular weight, small molecule heterocyclic ketone and thioester compounds, compositions containing the same, and the use of such compounds for treating neurological disorders, including physically damaged nerves and neurodegenerative diseases.

This application is a continuation of U.S. patent application Ser. No.10/104,242 filed on Mar. 25, 2002, now abandoned, which in turn is acontinuation of U.S. patent application Ser. No. 09/733,037 filed onDec. 11, 2000, now U.S. Pat. No. 6,417,209, which in turn is adivisional of U.S. patent application Ser. No. 09/444,200 filed on Nov.22, 1999, now U.S. Pat. No. 6,218,424, which in turn is acontinuation-in-part of U.S. patent application Ser. No. 08/904,461,filed Aug. 1, 1997, now U.S. Pat. No. 5,990,131, which is in turn acontinuation-in-part of U.S. patent application Ser. No. 08/721,765,filed Sep. 25, 1996, now U.S. Pat. No. 5,786,378, the entire contents ofwhich are considered a part of this application and are herebyincorporated by reference.

BACKGROUND OF THE INVENTION

This invention relates to neurotrophic, low molecular weight, smallmolecule heterocyclic ketone and thioester compounds, and their use foreffecting neuronal activities in animals, including treatingneurological disorders.

It has been found that picomolar concentrations of an immunosuppressant,such as FK506 or rapamycin, stimulates neurite outgrowth in PC12 cellsand sensory neurons, namely dorsal root ganglion cells (DRGs). Lyons etal., Proc. of Natl. Acad. Sci., 1994, vol. 91, pp. 3191-3195. In wholeanimal experiments, FK506 has been shown to stimulate nerve regenerationfollowing facial nerve injury and results in functional recovery inanimals with sciatic nerve lesions.

Studies have demonstrated that neurodegenerative disorders, such assenile dementia of the Alzheimer's type (SDAT or Alzheimer's disease),Parkinson's disease and amyotrophic lateral sclerosis (ALS), may occurdue to the loss, or decreased availability, of a neurotrophic substancespecific for a particular population of neurons affected in thedisorder. Several neurotrophic factors affecting specific neuronalpopulations in the central nervous system have been identified.

For example, it has been hypothesized that Alzheimer's disease resultsfrom a decrease or loss of nerve growth factor (NGF). It has thus beenproposed to treat SDAT patients with exogenous nerve growth factor orother neurotrophic proteins, such as brain derived growth factor, glialderived growth factor, ciliary neurotrophic factor and neurotropin-3, toincrease the survival of degenerating neuronal populations.

Clinical application of these proteins in various neurological diseasestates is hampered by difficulties in the delivery and bioavailabilityof large proteins to nervous system targets. By contrast,immunosuppressant drugs with neurotrophic activity are relatively smalland display excellent bioavailability and specificity. However, whenadministered chronically, immunosuppressants exhibit a number ofpotentially serious side effects, including nephrotoxicity, such asimpairment of glomerular filtration and irreversible interstitialfibrosis (Kopp et al., J. Am. Soc. Nephrol., 1991, 1:162); neurologicaldeficits, such as involuntary tremors, or non-specific cerebral angina,such as non-localized headaches (De Groen et al., N. Engl. J. Med.,1987, 317:861); and vascular hypertension, with complications resultingtherefrom (Kahan et al., N. Engl. J. Med., 1989, 321:1725).

To avoid the drawbacks associated with use of large molecule proteinsand/or immunosuppressants, the present invention provides small moleculecompounds for enhancing neurite outgrowth, and promoting neuronal growthand regeneration in various neuropathological situations where neuronalrepair can be facilitated, including: peripheral nerve damage caused byphysical injury or disease state such as diabetes; physical damage tothe central nervous system (spinal cord and brain); brain damageassociated with stroke; and neurological disorders relating toneurodegeneration, such as Parkinson's disease, Huntington's Disease,SDAT (Alzheimer's disease) and amyotrophic lateral sclerosis (ALS).

SUMMARY OF THE INVENTION

The present invention relates to neurotrophic, low molecular weight,small molecule heterocyclic ketone or thioester compounds. In apreferred embodiment, the compounds are non-immunosuppressive. Inanother preferred embodiment, the compounds of the present inventionhave an affinity for FKBP-type immunophilins, such as FKBP12; andaffinity binding or interaction may inhibit the prolyl-peptidylcis-trans isomerase, or rotamase, activity of the binding protein.

The present invention also relates to a pharmaceutical compositioncomprising:

-   -   (i) an effective amount of a neurotrophic, low molecular weight,        small molecule heterocyclic ketone or thioester compound; and    -   (ii) a pharmaceutically acceptable carrier.

The present invention further relates to a method of effecting aneuronal activity in an animal, comprising administering to said animalan effective amount of a neurotrophic, low molecular weight, smallmolecule heterocyclic ketone or thioester compound.

Specifically, the present invention relates to a compound of formula II:

or a pharmaceutically acceptable salt, ester, or solvate thereof,wherein:

n is 1 or 2;

X is O or S;

Z is selected from the group consisting of S, CH₂, CHR₁, CR₁R₂, and abond;

R₁, R₂, and R₃ are independently selected from the group consisting ofC₁-C₅ straight or branched chain alkyl, C₂-C₅ straight or branched chainalkenyl, and Ar, wherein said R₁, R₂, or R₃ is unsubstituted orsubstituted with one or more halo, trifluoromethyl, nitro, C₁-C₆straight or branched chain alkyl, C₂-C₆ straight or branched chainalkenyl, hydroxy, C₁-C₄ alkoxy, C₂-C₄ alkenyloxy, phenoxy, benzyloxy,amino, or Ar;

R₄ is selected from the group consisting of C₁-C₉ straight or branchedchain alkyl, C₂-C₉ straight or branched chain alkenyl, C₃-C₈ cycloalkyl,C₅-C₇ cycloalkenyl, and Ar; and

Ar is aryl.

The present invention also relates to a pharmaceutical compositioncomprising:

-   -   (i) an effective amount of the compound of formula II; and    -   (ii) a pharmaceutically acceptable carrier.

The present invention further relates to a method of effecting aneuronal activity in an animal, comprising administering to said animalan effective amount of a compound of formula II.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1(A) is a representative photomicrograph of untreated sensoryneurons.

FIG. 1(B) is a representative photomicrograph of compound 1 (10 pM)promoting neurite outgrowth in sensory neurons.

FIG. 1(C) is a representative photomicrograph of compound 1 (1 nM)promoting neurite outgrowth in sensory neurons.

FIG. 1(D) is a representative photomicrograph of compound 1 (1 μM)promoting neurite outgrowth in sensory neurons.

FIG. 2(A) is a representative photomicrograph of untreated sensoryneurons.

FIG. 2(B) is a representative photomicrograph of a related compound,2-Phenyl-1-ethyl(2S)-1-(3,3-dimethyl-1,2-dioxopentyl)-2-pyrrolidinecarbothioate,(10 pM) promoting neurite outgrowth in sensory neurons.

FIG. 2(C) is a representative photomicrograph of a related compound,2-Phenyl-1-ethyl(2S)-1-(3,3-dimethyl-1,2-dioxopentyl)-2-pyrrolidinecarbothioate,(1 nM) promoting neurite outgrowth in sensory neurons.

FIG. 2(D) is a representative photomicrograph of a related compound,2-Phenyl-1-ethyl(2S)-1-(3,3-dimethyl-1,2-dioxopentyl)-2-pyrrolidinecarbothioate,(100 nM) promoting neurite outgrowth in sensory neurons.

FIG. 3(A) is a representative photomicrograph of untreated sensoryneurons.

FIG. 3(B) is a representative photomicrograph of a related compound,2-Phenyl-1-ethyl1-(3,3-dimethyl-1,2-dioxopentyl)-2-piperidinecarbothioate, (10 pM)promoting neurite outgrowth in sensory neurons.

FIG. 3(C) is a representative photomicrograph of a related compound,2-Phenyl-1-ethyl1-(3,3-dimethyl-1,2-dioxopentyl)-2-piperidinecarbothioate, (1 nM)promoting neurite outgrowth in sensory neurons.

FIG. 3(D) is a representative photomicrograph of a related compound,2-Phenyl-1-ethyl1-(3,3-dimethyl-1,2-dioxopentyl)-2-piperidinecarbothioate, (100 nM)promoting neurite outgrowth in sensory neurons.

FIG. 4 presents quantitation for the recovery of TH-positivedopaminergic neurons in the striatum of animals receiving compound 1 andrelated compounds.

DETAILED DESCRIPTION OF THE INVENTION Definitions

“Alkenyl” means a branched or unbranched unsaturated hydrocarbon chaincomprising a designated number of carbon atoms. For example, C₂-C₆straight or branched alkenyl hydrocarbon chain contains 2 to 6 carbonatoms having at least one double bond, and includes but is not limitedto substituents such as ethenyl, propenyl, iso-propenyl, butenyl,iso-butenyl, tert-butenyl, n-pentenyl, n-hexenyl, and the Like. It isalso contemplated as within the scope of the present invention that“alkenyl” may also refer to an unsaturated hydrocarbon chain wherein anyof the carbon atoms of said alkenyl are optionally replaced with O, NH,S, or SO₂. For example, carbon 2 of 4-pentene can be replaced with O toform (2-propene)oxymethyl.

“Alkoxy” refers to the group —OR wherein R is alkyl as herein defined.Preferably, R is a branched or unbranched saturated hydrocarbon chaincontaining 1 to 6 carbon atoms.

“Alkyl” means a branched or unbranched saturated hydrocarbon chaincomprising a designated number of carbon atoms. For example, C₁-C₆straight or branched alkyl hydrocarbon chain contains 1 to 6 carbonatoms, and includes but is not limited to substituents such as methyl,ethyl, propyl, iso-propyl, butyl, iso-butyl, tert-butyl, n-pentyl,n-hexyl, and the like. It is also contemplated as within the scope ofthe present invention that “alkyl” may also refer to a hydrocarbon chainwherein any of the carbon atoms of said alkyl are optionally replacedwith O, NH, S, or SO₂. For example, carbon 2 of n-pentyl can be replacedwith O to form propyloxymethyl.

Throughout this application, “R” or “R_(n)”, where n is a number, isused to designate various substituents. These R groups are independentlyselected. Thus, for example, the fact that R₁ may be a branched alkyl inone context does not require that R₁ be the same branched alkyl, anddoes not prohibit that R₁ be, for example, a straight chain alkenyl inanother context in the same molecule. It is intended that all “R_(n)”are selected independently of all other “R_(n)”, whether or not the term“independently selected” is used.

“Aryl” or “aromatic” refers to an aromatic carbocyclic or heterocyclicgroup having a single ring, for example a phenyl ring; multiple rings,for example biphenyl; or multiple condensed rings in which at least onering is aromatic, for example naphthyl, 1,2,3,4-tetrahydronaphthyl,anthryl, or phenanthryl. The ring(s) of an aryl moiety can beunsubstituted or substituted with one or more substituents including,but not limited to, halo, hydroxyl, nitro, trifluoromethyl, C₁-C₆straight or branched chain alkyl or alkenyl, C₁-C₄ alkoxy, C₁-C₄alkenyloxy, phenoxy, benzyloxy, or amino; a heterocyclic ring maycontain 1-6 heteroatom(s) selected from the group consisting of O, N,and S. The substituents attached to a phenyl ring portion of an arylmoiety in the compounds of the invention may be configured in theortho-, meta-, or para-orientation(s), with the para-orientation beingpreferred.

Examples of typical aryl moieties included in the scope of the presentinvention may include, but are not limited to, the following:

It should be kept in mind that, throughout this application, “Ar” or“Ar_(n)”, where n is a number, is used to designate varioussubstituents. As indicated throughout, these Ar groups are independentlyselected. Thus, for example, the fact that Ar may be phenyl in onecontext does not require that Ar be phenyl, nor prohibit that Ar be, forexample, pyridyl in another context in the same molecule. It is intendedthat all “Ar” are selected independently of all other “Ar”, whether ornot the term “independently selected” is used.

“Carbocycle” or “carbocyclic” refers to an organic cyclic moiety inwhich the cyclic skeleton is comprised of only carbon atoms, whereas theterm “heterocycle” or “heterocyclic” refers to an organic cyclic moietyin which the cyclic skeleton contains one or more heteroatoms selectedfrom nitrogen, oxygen, or sulfur, and which may or may not includecarbon atoms. The term “carbocycle” refers to a carbocyclic moietycontaining the indicated number of carbon atoms. The term “C₃-C₈cycloalkyl”, therefore, refers to an organic cyclic substituent in whichthree to eight carbon atoms form a three, four, five, six, seven, oreight-membered ring, including, for example, a cyclopropyl, cyclobutyl,cyclopentyl, cyclohexyl, cycloheptyl, or cyclooctyl ring.

“Carbocyclic” or “heterocyclic” each includes within its scope a singlering system, multiple fused rings (for example, bicyclic, tricyclic, orother similar bridged ring systems or substituents, e.g. adamantyl) ormultiple condensed ring systems. One skilled in the art, therefore, willappreciate that in the context of the present invention, a cyclicstructure may comprise bi-, or tri-, or multiple condensed rings,bridged ring systems, or combinations thereof.

“Halo” refers to fluoro, chloro, bromo or iodo, unless otherwiseindicated.

“Heterocycle” or “heterocyclic”, refers to a saturated, unsaturated, oraromatic carbocyclic group having a single ring, multiple fused rings(for example, bicyclic, tricyclic, or other similar bridged ring systemsor substituents), or multiple condensed rings, and having at least oneheteroatom such as nitrogen, oxygen, or sulfur within at least one ofthe rings. This term also includes “Heteroaryl,” which refers to aheterocycle in which at least one ring is aromatic. Any heterocyclic orheteroaryl group can be unsubstituted or optionally substituted with oneor more groups, as defined above. Further, bi- or tricyclic heteroarylmoieties may comprise at least one ring which is either completely orpartially saturated.

As one skilled in the art will appreciate, such heterocyclic moietiesmay exist in several isomeric forms, all of which are encompassed by thepresent invention. For example, a 1,3,5-triazine moiety is isomeric to a1,2,4-triazine group. Such positional isomers are to be consideredwithin the scope of the present invention. Likewise, the heterocyclic orheteroaryl groups can be bonded to other moieties in the compounds ofthe present invention. The point(s) of attachment to these othermoieties is not to be construed as limiting on the scope of theinvention. Thus, by way of example, a pyridyl moiety may be bound toother groups through the 2-, 3-, or 4-position of the pyridyl group. Allsuch configurations are to be construed as within the scope of thepresent invention.

Examples of heterocyclic or heteroaryl moieties included in the scope ofthe present invention may include, but are not limited to, thefollowing:

“Isomers” are different compounds that have the same molecular formula.“Stereoisomers” are isomers that differ only in the way the atoms arearranged in space. “Enantiomers” are a pair of stereoisomers that arenon-superimposable mirror images of each other. “Diastereoisomers” arestereoisomers which are not mirror images of each other. “Racemicmixture” means a mixture containing equal parts of individualenantiomers. “Non-racemic mixture” is a mixture containing unequal partsof individual enantiomers or stereoisomers.

“Low molecular weight, small molecule compounds” include, withoutlimitation, molecules which are smaller in size, molecular weight, orboth in relation to the compounds Rapamycin, Cyclosporin, and FK506.

“Neurotrophic” includes without limitation the ability to stimulateneuronal regeneration or growth, the ability to prevent or treatneurodegeneration, or both.

“Non-immunosuppressive” refers to the inability of the compounds of thepresent invention to suppress an immune response when compared to acontrol such as FK506 or cyclosporin A. Assays for determiningimmunosuppression are well known to those of ordinary skill in the art.Specific, non-limiting examples of well known assays include PMA andOKT3, wherein mitogens are used to stimulate proliferation of humanperipheral blood lymphocytes (PBC) and the tested compounds areevaluated on their ability to inhibit such proliferation.

“Pharmaceutically acceptable carrier” refers to any carrier, diluent,excipient, suspending agent, lubricating agent, adjuvant, vehicle,delivery system, emulsifier, disintegrant, absorbant, preservative,surfactant, colorant, flavorant, or sweetener. For these purposes, thecompounds of the present invention may be administered orally,parenterally, by inhalation spray, topically, rectally, nasally,buccally, vaginally or via an implanted reservoir in dosage formulationscontaining conventional non-toxic pharmaceutically-acceptable carriers,adjuvants and vehicles. The term parenteral as used herein includessubcutaneous, intravenous, intramuscular, intraperitoneally,intrathecally, intraventricularly, intrasternal, and intracranialinjection or infusion techniques.

“Pharmaceutically acceptable salt”, refers to an organic or inorganicsalt which is useful in the treatment of a warm-blooded animal in needthereof. Such salts can be acid or basic addition salts, depending onthe nature of the inventive compound to be used.

In the case of an acidic moiety in an inventive compound, a salt may beformed by treatment of the inventive compound with a basic compound,particularly an inorganic base. Preferred inorganic salts are thoseformed with alkali and alkaline earth metals such as lithium, sodium,potassium, barium, and calcium. Preferred organic base salts include,for example, ammonium, dibenzylammonium, benzylammonium,2-hydroxyethylammonium, bis(2-hydroxyethyl)ammonium,phenylethylbenzylamine, dibenzyl-ethylenediamine, and like salts. Othersalts of acidic moieties may include, for example, those salts formedwith procaine, quinine and N-methylglucosamine, plus salts formed withbasic amino acids such as glycine, ornithine, histidine, phenylglycine,lysine and arginine. Other suitable base salts, esters, or solvatesinclude magnesium salts; salts with organic bases, such asdicyclohexylamine salts; and N-methyl-D-glucamine. An especiallypreferred salt is a sodium or potassium salt of an inventive compound.

With respect to basic moieties, a salt is formed by the treatment of thedesired inventive compound with an acidic compound, particularly aninorganic acid. Preferred inorganic salts of this type may include, forexample, hydrochloric, hydrobromic, hydroiodic, sulfuric, phosphoric; orlike salts. Preferred organic salts of this type, may include, forexample, salts formed with formic, acetic, succinic, citric, lactic,maleic, fumaric, palmitic, cholic, pamoic, mucic, d-glutamic,d-camphoric, glutaric, glycolic, phthalic, tartaric, lauric, stearic,salicyclic, methanesulfonic, benzenesulfonic, para-toluenesulfonic,sorbic, puric, benzoic, cinnamic, and like organic acids. Other suitableacids are adipate, alginate, aspartate, benzenesulfonate, bisulfate,butyrate, camphorsulfonate, cyclopentanepropionate, digluconate,dodecylsulfate, ethanesulfonate, glucoheptanoate, glycerophosphate,hemisulfate, heptanoate, hexanoate, 2-hydroxyethanesulfonate,methanesulfonate, naphthylate, 2-naphthalenesulfonate, nicotinate,oxalate, thiocyanate, tosylate, and undecanoate. An especially preferredsalt of this type is a hydrochloride or sulfate salt of the desiredinventive compound. Also, the basic nitrogen-containing groups can bequarternized with such agents as: 1) lower alkyl halides, such asmethyl, ethyl, propyl, and butyl chlorides, bromides, and iodides; 2)dialkyl sulfates like dimethyl, diethyl, dibutyl, and diamyl sulfates;3) long chain alkyls such as decyl, lauryl, myristyl, and stearylsubstituted with one or more halide such as chloride, bromide, andiodide; and 4) aralkyl halides like benzyl and phenethyl bromide andothers.

Also encompassed in the scope of the present invention arepharmaceutically acceptable esters of a carboxylic acid or hydroxylcontaining group, including a metabolically labile ester or a prodrugform of an inventive compound. A metabolically labile ester is one whichmay produce, for example, an increase in blood levels and prolong theefficacy of the corresponding non-esterified form of the compound. Aprodrug form is one which is not in an active form of the molecule asadministered but which becomes therapeutically active after some in vivoactivity or biotransformation, such as, for example, metabolism byenzymatic or hydrolytic cleavage. Esters of an inventive compound mayinclude, for example, methyl, ethyl, propyl, and butyl esters, as wellas other suitable esters formed between an acidic moiety and a hydroxylcontaining moiety. Metabolically labile esters may include, for example,methoxymethyl, ethoxymethyl, iso-propoxymethyl, α-methoxyethyl, andgroups such as α-((C₁-C₄)alkyloxy)ethyl; methoxyethyl, ethoxyethyl,propoxyethyl, and iso-propoxyethyl; 2-oxo-1,3-dioxolen-4-ylmethylgroups, such as 5-methyl-2-oxo-1,3,dioxolen-4-ylmethyl; C₁-C₃alkylthiomethyl groups, for example, methylthiomethyl, ethylthiomethyl,isopropylthiomethyl; acyloxymethyl groups, for example,pivaloyloxy-methyl, α-acetoxymethyl; ethoxycarbonyl-1-methyl; orα-acyloxy-α-substituted methyl groups, for example α-acetoxyethyl.

Further, the compounds of the invention may exist as crystalline solidswhich can be crystallized from common solvents such as ethanol,N,N-dimethyl-formamide, water, or the like. Thus, crystalline forms ofthe compounds of the invention may exist as solvates and/or hydrates ofthe parent compounds or their pharmaceutically acceptable salts, esters,or solvates. All of such forms likewise are to be construed as fallingwithin the scope of the invention.

“Phenyl” refers to any possible isomeric phenyl radical, optionallymonosubstituted or multisubstituted with substituents selected from thegroup consisting of alkyl, alkoxy, hydroxy, halo, and haloalkyl.

“Preventing neurodegeneration” includes (1) the ability to inhibit orprevent neurodegeneration in patients newly diagnosed as having aneurodegenerative disease or at risk of developing a newneurodegenerative disease and (2) the ability to inhibit or preventfurther neurodegeneration in patients who are already suffering from, orhave symptoms of, a neurodegenerative disease.

“Treating” or “treatment” covers any treatment of a disease, acondition, or both in an animal, particularly a human, and includes:

(i) preventing a disease or condition from occurring in a subject whichmay be predisposed to the disease or condition but has not yet beendiagnosed as having it;

(ii) inhibiting a disease or condition, i.e., arresting its development;or

(iii) relieving a disease or condition, i.e., causing regression of thedisease or condition.

“Warm-blooded animal” or “animal” includes a mammal, including a memberof the human, equine, porcine, bovine, murine, canine, or felinespecies. In the case of a human, the term “warm-blooded animal” or“animal” may also be referred to as a “patient”. Further, as usedherein, “a warm blooded animal in need thereof” refers to a warm-bloodedanimal which is susceptible to a disorder due to genetic orenvironmental conditions or predispositions. This term also refers to awarm blooded animal which has already suffered some degree of injury ordamage because of genetic or environmental conditions to which theanimal has been exposed or to which it is or was predisposed.Environmental conditions can include treatment with a therapeuticcompound, as well as other types of injury or insult.

Compounds of the Invention

The present invention relates to low molecular weight, small moleculeneurotrophic compounds. In a preferred embodiment, the compounds of thepresent invention do not exert any significant immunosuppressiveactivity. In another preferred embodiment, the compounds of the presentinvention may bind to, or otherwise interact with, FKBP-typeimmunophilins, such as FKBP12; such binding or interaction may inhibitthe prolyl-peptidyl cis-trans isomerase, or rotamase, activity of thebinding protein.

In another preferred embodiment, the compound of the presents inventionhas a molecular weight no more than about 800 daltons. In a morepreferred embodiment, the compound of the present invention has amolecular weight no more than about 500 daltons. In a particularlypreferred embodiment, the compound of the present invention has amolecular weight no more than about 330 daltons.

In another preferred embodiment, the compound of the present inventionexhibits a Chick Dorsal Root Ganglion Neurite Outgrowth Assay (“DRG”)ED₅₀ value which is less than about 10 nM. In a more preferredembodiment, the compound of the present invention exhibits a DRG ED₅₀value which is less than about 1.0 nM. In a particularly preferredembodiment, the compound of the present invention exhibits a DRG ED₅₀value which is less than about 0.1 nM.

In another preferred embodiment, the compound of the present inventionexhibits an MPTP Assay value which is greater than about 20% recovery ofTH-stained dopaminergic neurons. In a more preferred embodiment, thecompound of the present invention exhibits an MPTP Assay value which isgreater than about 35% recovery of TH-stained dopaminergic neurons. In aparticularly preferred embodiment, the compound of the present inventionexhibits an MPTP Assay value which is greater than about 50% recovery ofTH-stained dopaminergic neurons.

Formula I

A preferred embodiment of this invention is a compound of formula I:

or a pharmaceutically acceptable salt, ester, or solvate thereof,wherein:

A and B, together with the nitrogen and carbon atoms to which they arerespectively-attached, form a 5-7 membered saturated or unsaturatedheterocyclic ring containing any combination of CH₂, O, S, SO, SO₂, NH,or NR₄ in any chemically stable oxidation state;

X is either O or S;

Z is either S, CH₂, CHR₁, CR₁R₂, or a bond;

W and Y are independently O, S, CH₂, or H₂;

R₁, R₂, and R₃ are independently C₁-C₆ straight or branched chain alkylor alkenyl, which is substituted in one or more position(s) with(Ar₁)_(n), (Ar₁)_(n) connected by a C₁-C₆ straight or branched chainalkyl or alkenyl, C₃-C₉ cycloalkyl, C₃-C₈ cycloalkyl connected by aC₁-C₆ straight or branched chain alkyl or alkenyl, or Ar₂;

n is 1 or 2;

R₄ is either C₁-C₉ straight or branched chain alkyl, C₂-C₉ straight orbranched chain alkenyl, C₃-C₈ cycloalkyl, C₅-C₇ cycloalkenyl or Ar₁,wherein said alkyl, alkenyl, cycloalkyl or cycloalkenyl is eitherunsubstituted or substituted in one or more position(s) with C₁-C₄straight or branched chain alkyl or alkenyl, or hydroxyl; and

Ar₁ and Ar₂ are each, independently, an aryl group. A preferredembodiment of an aryl group is a mono-, bi- or tricyclic, carbo- orheterocyclic ring, wherein the ring is either unsubstituted orsubstituted in one or more position(s) with halo, hydroxyl, nitro,trifluoromethyl, C₁-C₆ straight or branched chain alkyl or alkenyl,C₁-C₄ alkoxy, C₁-C₄ alkenyloxy, phenoxy, benzyloxy, or amino; whereinthe individual ring sizes are 5-6 members; and wherein the heterocyclicring contains 1-6 heteroatom(s) selected from the group consisting of O,N, and S.

Suitable mono- and bicyclic, carbo- and heterocyclic rings include,without limitation, naphthyl, indolyl, thioindolyl, furyl, thiazolyl,thienyl, pyridyl, quinolinyl, isoquinolinyl, fluorenyl, phenyl, andbenzyl.

Formula II

Another preferred embodiment of this invention is a compound of formulaII:

or a pharmaceutically acceptable salt, ester, or solvate thereof,wherein:

n is 1 or 2;

X is O or S;

Z is selected from the group consisting of S, CH₂, CHR₁, CR₁R₂ and abond;

R₁, R₂, and R₃ are independently selected from the group consisting ofC₁-C₅ straight or branched chain alkyl, C₂-C₅ straight or branched chainalkenyl, and Ar, wherein said R₁, R₂, or R₃ is unsubstituted orsubstituted with one or more halo, trifluoromethyl, nitro, C₁-C₆straight or branched chain alkyl, C₂-C₆ straight or branched chainalkenyl, hydroxy, C₁-C₄ alkoxy, C₂-C₄ alkenyloxy, phenoxy, benzyloxy,amino, or Ar;

R₄ is selected from the group consisting of C₁-C₉ straight or branchedchain alkyl, C₂-C₉ straight or branched chain alkenyl, C₃-C₈ cycloalkyl,C₅-C₇ cycloalkenyl, and Ar; and

Ar is aryl. A preferred embodiment for Ar is phenyl, benzyl, pyridyl,fluorenyl, thioindolyl, or naphthyl, wherein said Ar is unsubstituted orsubstituted with one or more substituents independently selected fromthe group consisting of halo, trifluoromethyl, hydroxy, nitro, C₁-C₆straight or branched chain alkyl, C₂-C₆ straight or branched chainalkenyl, C₁-C₄ alkoxy, C₂-C₄ alkenyloxy, phenoxy, benzyloxy, and amino.

A particularly preferred embodiment of Formula II is a compound whereinn is 1, X is O, Z is CH₂, R₃ is 3-pyridylpropyl, and R₄ is1,1-dimethylpropyl.

Another particularly preferred embodiment of Formula II is a compoundwherein n is 2, X is O, Z is CH₂, R₃ is 4-phenylbutyl, and R₄ is1,1-dimethylpropyl.

Another particularly preferred embodiment of Formula II is a compoundwherein n is 1, X is O, z is CH₂, R₃ is 2-phenylethyl, and R₄ istert-butyl.

Another particularly preferred embodiment of Formula II is a compoundwherein n is 1, X is O, Z is CH₂, R₃ is 3-(4-hydroxyphenyl)propyl, andR₄ is 1,1-dimethylpropyl.

The most preferred embodiments of Formula II are(2S)-3,3-dimethyl-1-[2-(5-(3-pyridyl)pyrrolidinyl]pentane-1,2-dione;2-({1-oxo-6-phenyl}-hexyl)(2S)-1-(3,3-dimethyl-1,2-dioxopentyl)piperidine;2-(1-Oxo-4-phenyl)-butyl-1-(3,3-dimethyl-1,2-dioxobutyl)pyrrolidine; and(2S)-3,3-dimethyl-1-[2-(5-(4-hydroxyphenyl)pentanoyl)pyyrolidinyl]pentane-1,2-dione.

Specific examples of the embodiments of Formula II are presented inTABLE I. The molecular weights of the specifically exemplified compoundsis between about 330 daltons and about 500 daltons.

TABLE I

No. n X Z R₃ R₄  1 1 O CH₂ 3-Phenylpropyl 1,1-Dimethylpropyl  2 1 O CH₂3-(3-Pyridyl)propyl 1,1-Dimethylpropyl  3 1 O CH₂ 3-Phenylpropyltert-Butyl  4 1 O CH₂ 3-(3-Pyridyl)propyl tert-Butyl  5 1 O CH₂3-(3-Pyridyl)propyl Cyclohexyl  6 1 O CH₂ 3-(3-Pyridyl)propylCyclopentyl  7 1 O CH₂ 3-(3-Pyridyl)propyl Cycloheptyl  8 1 O CH₂2-(9-Fluorenyl)ethyl 1,1-Dimethylpropyl  9 1 O S 2-Phenethyl1,1-Dimethylpropyl 10 2 O S 2-Phenethyl 1,1-Dimethylpropyl 11 1 O SMethyl(2-thioindole) 1,1-Dimethylpropyl 12 1 O S 2-Phenethyl Cyclohexyl13 2 O S 2-Phenethyl tert-Butyl 14 2 O S 2-Phenethyl Phenyl 15 1 O CH₂3-(4-Methoxyphenyl) 1,1-Dimethylpropyl propyl 16 2 O CH₂4-(4-Methoxyphenyl) 1,1-Dimethylpropyl butyl 17 2 O CH₂ 4-Phenylbutyl1,1-Dimethylpropyl 18 2 O CH₂ 4-Phenylbutyl Phenyl 19 2 O CH₂4-Phenylbutyl tert-Butyl 20 1 S CH₂ 3-Phenylpropyl 1,1-Dimethylpropyl 211 S S 2-Phenethyl 1,1-Dimethylpropyl 22 2 S CH₂ 3-Phenylpropyl1,1-Dimethylpropyl 23 2 S S 2-Phenethyl 1,1-Dimethylpropyl 24 1 O S2-Phenethyl Cyclopentyl 25 2 O S 3-Phenylpropyl tert-Butyl 26 1 O S3-Phenylpropyl 1,1-Dimethylpropyl 27 1 O S 3-(3-Pyridyl)propyl1,1-Dimethylpropyl 28 1 O S 3-Phenylpropyl Cyclohexyl 29 1 O S4-Phenylbutyl Cyclohexyl 30 1 O S 4-Phenylbutyl 1,1-Dimethylpropyl 31 1O S 3-(3-Pyridyl)propyl Cyclohexyl 32 1 O S 3,3-Diphenylpropyl1,1-Dimethylpropyl 33 1 O S 3,3-Diphenylpropyl Cyclohexyl 34 1 O S3-(4-Methoxyphenyl) 1,1-Dimethylpropyl propyl 35 2 O S 4-Phenylbutyltert-Butyl 36 2 O S 1,5-Diphenyl-3-pentyl 1,1-Dimethylpropyl 37 2 O S1,5-Diphenyl-3-pentyl Phenyl 38 2 O S 3-(4-Methoxyphenyl)1,1-Dimethylpropyl propyl 39 2 O S 3-(4-Methoxyphenyl) Phenyl propyl 402 O S 3-(1-Naphthyl)propyl 1,1-Dimethylpropyl 41 1 O S3,3-Di(4-fluoro)phenyl- 1,1-Dimethylpropyl propyl 42 1 O S4,4-Di(4-fluoro)phenyl- 1,1-Dimethylpropyl butyl 43 1 O S3-(1-Naphthyl)propyl 1,1-Dimethylpropyl 44 1 O S 2,2-Diphenylethyl1,1-Dimethylpropyl 45 2 O S 2,2-Diphenylethyl 1,1-Dimethylpropyl 46 2 OS 3,3-Diphenylpropyl 1,1-Dimethylpropyl 47 1 O S 3-(4-{Trifluoromethyl}-1,1-Dimethylpropyl phenyl)propyl 48 1 O S 3-(2-Naphthyl)propyl1,1-Dimethylpropyl 49 2 O S 3-(1-Naphthyl)propyl 1,1-Dimethylpropyl 50 1O S 3-(3-Chloro)phenyl- 1,1-Dimethylpropyl propyl 51 1 O S3-(3-{Trifluoromethyl}- 1,1-Dimethylpropyl phenyl)propyl 52 1 O S3-(2-Biphenyl)propyl 1,1-Dimethylpropyl 53 1 O S3-(2-Fluorophenyl)propyl 1,1-Dimethylpropyl 54 1 O S3-(3-Fluorophenyl)propyl 1,1-Dimethylpropyl 55 2 O S 4-Phenylbutyl1,1-Dimethylpropyl 56 2 O S 3-Phenylpropyl 1,1-Dimethylpropyl 57 1 O S3-(2-Chloro)phenyl- 1,1-Dimethylpropyl propyl 58 2 O S3-(3-Chloro)phenyl- 1,1-Dimethylpropyl propyl 59 2 O S3-(2-Fluoro)phenylpropyl 1,1-Dimethylpropyl 60 2 O S3-(3-Fluoro)phenylpropyl 1,1-Dimethylpropyl 61 1 O S 3-(3,4-Dimethoxy-1,1-Dimethylpropyl phenyl)propyl 62 1 O CH₂ 3-Phenylpropyl Cyclohexyl 631 O CH₂ 2-Phenylethyl tert-Butyl 64 2 O CH₂ 4-Phenylbutyl Cyclohexyl 652 O CHR₁ 2-Phenylethyl tert-Butyl 66 1 O CH₂ 3,3-Di(4-fluorophenyl)-1,1-Dimethylpropyl propyl 67 2 O CH₂ 3-Phenylpropyl 1,1-Dimethylpropyl68 1 O CH₂ 3-(4-Hydroxy- 1,1-Dimethylpropyl phenyl)propyl 69 1 O bond3-Phenylpropyl 1,1-Dimethylpropyl 70 1 O bond 3-(3-Pyridyl)propyltert-Butyl 71 1 O bond 3-(3-Pyridyl)propyl Cyclohexyl 72 2 O bond4-(4-Methoxy- 1,1-Dimethylpropyl phenyl)butyl 73 2 O bond 4-Phenylbutyl1,1-Dimethylpropyl 74 2 O bond 4-Phenylbutyl Phenyl

The most preferred examples of the compounds of TABLE I are named asfollows:

-   1    (2S)-3,3-dimethyl-1-[2-(5-phenylpentanoyl)pyrrolidinyl]pentane-1,2-dione-   2    (2S)-3,3-dimethyl-1-[2-(5-(3-pyridyl)pyrrolidinyl]pentane-1,2-dione-   3    (2S)-2-({1-oxo-5-phenyl}-pentyl-1-(3,3-dimethyl-1,2-dioxobutyl)pyrrolidine-   9 2-Phenyl-1-ethyl    (2S)-1-(3,3-dimethyl-1,2-dioxopentyl)-2-pyrrolidinecarbothioate-   10 2-Phenyl-1-ethyl    1-(3,3-dimethyl-1,2-dioxopentyl)-2-piperidinecarbothioate-   11    1-{2-benzo[b]thiophen-3-ylmethylthio)carbonyl]pyrrolidinyl}-3,3-dimethylpentane-1,2-dione-   12 2-Phenyl-1-ethyl    (2S)-1-(2-cyclohexyl-1,2-dioxoethyl)-2-pyrrolidinecarbothioate-   14 2-Phenyl-1-ethyl    1-(2-phenyl-1,2-dioxoethyl)-2-piperidinecarbothioate-   17 2-({1-oxo-6-phenyl}-hexyl)    (2S)-1-(3,3-dimethyl-1,2-dioxopentyl)piperidine-   24 2-Phenyl-1-ethyl    (2S)-1-(1-cyclopentyl-1,2-dioxoethyl)-2-pyrrolidinecarbothioate-   25 3-Phenyl-1-propyl    1-(3,3-dimethyl-1,2-dioxobutyl)-2-piperidinecarbothioate-   26 3-Phenyl-1-propyl    (2S)-1-(3,3-dimethyl-1,2-dioxopentyl)-2-pyrrolidinecarbothioate-   27 3-(3-Pyridyl)-1-propyl    (2S)-1-(3,3-dimethyl-1,2-dioxopentyl)-2-pyrrolidinecarbothioate-   28 3-Phenyl-1-propyl    (2S)-1-(2-cyclohexyl-1,2-dioxoethyl)-2-pyrrolidinecarbothioate-   29 4-Phenyl-1-butyl    (2S)-1-(2-cyclohexyl-1,2-dioxoethyl)-2-pyrrolidinecarbothioate-   30 4-Phenyl-1-butyl    (2S)-1-(3,3-dimethyl-1,2-dioxopentyl)-2-pyrrolidinecarbothioate-   31 3-(3-Pyridyl)-1-propyl    (2S)-1-(2-cyclohexyl-1,2-dioxoethyl)-2-pyrrolidinecarbothioate-   32 3,3-Diphenyl-1-propyl    (2S)-1-(3,3-dimethyl-1,2-dioxopentyl)-2-pyrrolidinecarbothioate-   33 3,3-Diphenyl-1-propyl    (2S)-1-(2-cyclohexyl-1,2-dioxoethyl)-2-pyrrolidinecarbothioate-   34 3-(para-Methoxyphenyl)-1-propyl    (2S)-1-(3,3-dimethyl-1,2-dioxopentyl)-2-pyrrolidinecarbothioate-   35 4-Phenyl-1-butyl    1-(1,2-dioxo-3,3-dimethylbutyl)-2-piperidinecarbothioate-   36 1,5-Diphenyl-3-pentyl    1-(3,3-dimethyl-1,2-dioxopentyl)-2-piperidinecarbothioate-   37 1,5-Diphenyl-3-pentyl    1-(2-phenyl-1,2-dioxoethyl)-2-piperidinecarbothioate-   38 3-(para-Methoxyphenyl)-1-propyl    1-(1,2-dioxo-3,3-dimethylpentyl)piperidine-2-carbothioate-   39 3-(para-Methoxyphenyl)-1-propyl    1-(2-phenyl-1,2-dioxoethyl)piperidine-2-carbothioate-   40 3-(1-Naphthyl)-1-propyl    1-(3,3-dimethyl-1,2-dioxopentyl)piperidine-2-carbothioate-   41 3,3-Di(para-fluoro)phenyl-1-propyl    (2S)-1-(3,3-dimethyl-1,2-dioxopentyl)-2-pyrrolidinecarbothioate-   42 4,4-Di(para-fluorophenyl)butyl    1-(3,3-dimethyl-2-oxopentanoyl)-2-pyrrolidinecarbothioate-   43 3-(1-Naphthyl)-1-propyl    (2S)-1-(3,3-dimethyl-2-oxopentanoyl)-2-pyrrolidinecarbothioate-   44 2,2-Diphenylethyl    (2S)-1-(3,3-dimethyl-2-oxopentanoyl)-2-pyrrolidinecarbothioate-   45 2,2-Diphenylethyl    (2S)-1-(3,3-dimethyl-2-oxopentanoyl)-2-piperidinecarbothioate-   46 3,3-Diphenylpropyl    1-(3,3-dimethyl-2-oxopentanoyl)-2-piperidinecarbothioate-   47 3-[4-(Trifluoromethyl)phenyl]propyl    (2S)-1-(3,3-dimethyl-2-oxopentanoyl)-2-pyrrolidinecarbothioate-   48 3-(2-Naphthyl)propyl    (2S)-1-(3,3-dimethyl-2-oxopentanoyl)-2-pyrrolidinecarbothioate-   49 3-(1-Naphthyl)-1-propyl    1-(3,3-dimethyl-2-oxopentanoyl)-2-piperidinecarbothioate-   50 3-(3-Chlorophenyl)propyl    (2S)-1-(3,3-dimethyl-2-oxopentanoyl)-2-pyrrolidinecarbothioate-   51 3-[3-(Trifluoromethyl)phenyl]propyl    (2S)-1-(3,3-dimethyl-2-oxopentanoyl)-2-pyrrolidinecarbothioate-   52 3-(2-Biphenyl)propyl    (2S)-1-(3,3-dimethyl-2-oxopentanoyl)-2-pyrrolidinecarbothioate-   53 3-(2-Fluorophenyl)propyl    (2S)-1-(3,3-dimethyl-2-oxopentanoyl)-2-pyrrolidinecarbothioate-   54 3-(3-Fluorophenyl)propyl    (2S)-1-(3,3-dimethyl-2-oxopentanoyl)-2-pyrrolidinecarbothioate-   55 4-Phenylbutyl    1-(3,3-dimethyl-2-oxopentanoyl)-2-piperidinecarbothioate-   56 3-Phenylpropyl    1-(3,3-dimethyl-2-oxopentanoyl)-2-piperidinecarbothioate-   57 3-(2-Chlorophenyl)propyl    (2S)-1-(3,3-dimethyl-2-oxopentanoyl)-2-pyrrolidinecarbothioate-   58 3-(3-Chlorophenyl)-1-propyl    1-(3,3-dimethyl-2-oxopentanoyl)-2-piperidinecarbothioate-   59 3-(2-Fluorophenyl)propyl    1-(3,3-dimethyl-2-oxopentanoyl)-2-piperidinecarbothioate-   60 3-(3-Fluorophenyl)propyl    1-(3,3-dimethyl-2-oxopentanoyl)-2-piperidinecarbothioate-   61 3-(3,4-Dimethoxyphenyl)propyl    (2S)-1-(3,3-dimethyl-2-oxopentanoyl)-2-pyrrolidinecarbothioate-   62    (2S)-2-(1-Oxo-5-phenyl)pentyl-1-(2-Cyclohexyl-1,2-dioxoethyl)pyrrolidine-   63    2-(1-Oxo-4-phenyl)-butyl-1-(3,3-dimethyl-1,2-dioxobutyl)pyrrolidine-   64    2-(1-Oxo-6-phenyl)-hexyl-1-(2-Cyclohexyl-1,2-dioxoethyl)piperidine-   65    2-({1-Oxo-[2-{2′-phenyl}ethyl]-4-phenyl}-butyl-1-(3,3-dimethyl-1,2-dioxobutyl)piperidine-   66 (2S)-2-[5,5-di(4-Fluorophenyl)pentanoyl]-1-(3,3    dimethyl-1,2-pentanedione)pyrrolidine-   67 3,3-Dimethyl-1-[2-(5-phenylpentanoyl)piperidino]-1,2-pentanedione-   68 (2S)-3,3-dimethyl-1-[2-(5-(4-hydroxyphenyl)    pentanoyl)pyyrolidinyl]penatane-1,2-dione

Formula III

Another preferred embodiment is a compound of formula III:

or a pharmaceutically acceptable salt, ester, or solvate thereof,wherein:

A, B, and C are independently CH₂, O S, SO, SO₂, NH, or NR₄;

X is O or S;

Z is S, CH₂, CHR₁, or CR₁R₂;

R₁, R₂, and R₃ are independently C₁-C₆ straight or branched chain alkylor alkenyl, which is substituted in one or more position(s) with(Ar₁)_(n), (Ar_(l))_(n) connected by a C₁-C₆ straight or branched chainalkyl or alkenyl, C₃-C₈ cycloalkyl, C₃-C₈ cycloalkyl connected by aC₁-C₆ straight or branched chain alkyl at alkenyl, Ar₂, or a combinationthereof;

n is 1 or 2;

R₄ is either C₁-C₉ straight or branched chain alkyl or alkenyl, C₃-C₈cycloalkyl, C₅-C₇ cycloalkenyl or Ar₁, wherein said alkyl, alkenyl,cycloalkyl or cycloalkenyl is either unsubstituted or substituted in oneor more position(s) with C₁-C₄ straight or branched chain alkyl oralkenyl, hydroxyl, or a combination thereof; and

Ar₁ and Ar₂ are independently a mono-, bi- or tricyclic, carbo- orheterocyclic ring, wherein the ring is either unsubstituted orsubstituted in one to three position(s) with halo, hydroxyl, nitro,trifluoromethyl, C₁-C₆ straight or branched chain alkyl or alkenyl,C₁-C₄ alkoxy, C₁-C₄ alkenyloxy, phenoxy, benzyloxy, amino or acombination thereof; wherein the individual ring sizes are 5-6 members;and wherein the heterocyclic ring contains 1-6 heteroatom(s) selectedfrom the group consisting of O, N, S, and a combination thereof.

Particularly preferred compounds of formula III are presented in TABLEII.

TABLE II

No. A B C X Z R₃ R₄ 75 CH₂ S CH₂ O S 2-phenethyl 1,1-Dimethyl- propyl 76CH₂ S CH₂ O CH₂ 3-phenylpropyl 1,1-Dimethyl- propyl 77 CH₂ CH₂ NH O S2-phenethyl 1,1-Dimethyl- propyl 78 CH₂ S CH₂ S S 2-phenethyl1,1-Dimethyl- propyl

Formula IV

A further preferred embodiment of this invention is a compound offormula IV:

or a pharmaceutically acceptable salt, ester, or solvate thereof,wherein:

A, B, C, and D are independently CH₂, O, S, SO, SO₂, NH, or NR₄;

X is O or S;

Z is S, CH₂, CHR₁, or CR₁R₂;

R₁, R₂, and R₃ are independently C₁-C₆ straight or branched chain alkylor alkenyl, which is substituted in one or more position(s) with(Ar₁)_(n), (Ar₁)_(n) connected by a C₁-C₆ straight or branched chainalkyl or alkenyl, C₃-C₈ cycloalkyl, C₃-C₈ cycloalkyl connected by aC₁-C₆ straight or branched chain alkyl or alkenyl, Ar₂, or a combinationthereof;

n is 1 or 2;

R₄ is either C₁-C₉ straight or branched chain alkyl or alkenyl, C₃-C₈cycloalkyl, C₅-C₇ cycloalkenyl or Ar₁, wherein said alkyl, alkenyl,cycloalkyl or cycloalkenyl is either unsubstituted or substituted in oneor more position(s) with C₁-C₄ straight or branched chain alkyl oralkenyl, hydroxyl, or a combination thereof; and

Ar₁ and Ar₂ are independently a mono-, bi- or tricyclic, carbo- orheterocyclic ring, wherein the ring is either unsubstituted orsubstituted in one to three position(s) with halo, hydroxyl, nitro,trifluoromethyl, C₁-C₆ straight or branched chain alkyl or alkenyl,C₁-C₄ alkoxy, C₁-C₄ alkenyloxy, phenoxy, benzyloxy, amino, or acombination thereof; wherein the individual ring sizes are 5-6 members;and wherein the heterocyclic ring contains 1-6 heteroatom(s) selectedfrom the group consisting of O, N, S, and a combination thereof.

Particularly preferred compounds of formula IV are presented in TABLEIII.

TABLE III

No. A B C D X Z R₃ R₄ 79 CH₂ CH₂ O CH₂ O CH₂ 3-phenylpropyl 1,1-Dimethyl- propyl 80 CH₂ CH₂ O CH₂ O S 2-phenethyl 1,1- Dimethyl- propyl81 CH₂ CH₂ S CH₂ O CH₂ 3-phenylpropyl 1,1- Dimethyl- propyl 82 CH₂ CH₂ SCH₂ O S 2-phenethyl 1,1- Dimethyl- propyl

The compounds of this invention possess at least one asymmetric centerand thus can be produced as mixtures of stereoisomers or as individualR- and S-stereoisomers. The individual enantiomers may be obtained byusing an optically active starting material, by resolving a racemic ornon-racemic mixture of an intermediate at some appropriate stage of thesynthesis, or by resolving a compound of the present invention. It isunderstood that the individual R- and S-stereoisomers as well asmixtures (racemic and non-racemic) of stereoisomers are encompassed bythis invention. The S-stereoisomer is most preferred.

Synthesis of Pyrrolidine Derivatives

The compounds of formulas I to IV may be prepared by a variety ofsynthetic sequences that utilize established chemical transformations.The general pathway to the present compounds is described in Scheme I.Starting compounds may be reacted with a variety of alkenyl magnesiumhalides to form olefin intermediates (1), which are in turn reactedsequentially with trifluroacetic acid; then methyl oxalyl chloride andtriethylamine. The resulting oxamates (2) may be reacted with a varietyof carbon nucleophiles, such as R₁—MgCl, to obtain further olefinintermediates (3). These intermediates are then reacted with a varietyof organohalogen compounds, such as R₂—Br, to produce product (4), whichis hydrogenated to produce compounds of the present invention (5).

Methods of Using the Compounds of the Invention

The present invention further relates to the use of a compound of thepresent invention in the preparation of a medicament for effecting aneuronal activity in an animal.

Further, the present invention relates to a method of effecting aneuronal activity in an animal, comprising administering to said animala neurotrophically effective amount of a compound of the presentinvention.

As neurotrophic agents, the compounds of this invention can beperiodically administered to a patient undergoing treatment forneurological disorders or for other reasons in which it is desirable tostimulate neuronal regeneration and growth, such as in variousperipheral neuropathic and neurological disorders relating toneurodegeneration. The compounds of this invention can also beadministered to mammals other than humans for treatment of variousmammalian neurological disorders.

The novel compounds of the present invention possess an excellent degreeof neurotrophic activity. This activity is useful in the stimulation ofdamaged neurons, the promotion of neuronal regeneration, the preventionof neurodegeneration, and in the treatment of several neurologicaldisorders known to be associated with neuronal degeneration andperipheral neuropathies. The neurological disorders that may be treatedinclude but are not limited to: trigeminal neuralgia, glossopharyngealneuralgia, Bell's Palsy, myasthenia gravis, muscular dystrophy,amyotrophic lateral sclerosis, progressive muscular atrophy, progressivebulbar inherited muscular atrophy, herniated, ruptured or prolapsedinvertebrate disk syndromes, cervical spondylosis, plexus disorders,thoracic outlet destruction syndromes, peripheral neuropathies such asthose caused by lead, dapsone, ticks, prophyria, Gullain-Barré syndrome,Alzheimer's disease, Huntington's Disease, or Parkinson's disease.

For these purposes, the compounds may be administered orally,parenterally, by inhalation spray, topically, rectally, nasally,buccally, vaginally, or via an implanted reservoir in dosageformulations containing conventional non-toxicpharmaceutically-acceptable carriers, adjuvants, and vehicles. The termparenteral as used herein includes subcutaneous, intravenous,intramuscular, intraperitoneally, intrathecally, intraventricularly,intrasternal, and intracranial injection or infusion techniques.

To be effective therapeutically as central nervous system targets, thecompounds should readily penetrate the blood-brain barrier whenperipherally administered. Compounds which cannot penetrate theblood-brain barrier can be effectively administered by anintraventricular route.

The compounds may be administered in the form of sterile injectablepreparations, for example, as sterile injectable aqueous or oleaginoussuspensions. These suspensions, may be formulated according totechniques known in the art using suitable dispersing or wetting agentsand suspending agents. The sterile injectable preparations may also besterile injectable solutions or suspensions in non-toxicparenterally-acceptable diluents or solvents, for example, as solutionsin 1,3-butanediol. Among the acceptable vehicles and solvents that maybe employed are water, Ringer's solution and isotonic sodium chloridesolution. In addition, sterile, fixed oils are conventionally employedas solvents or suspending mediums. For this purpose, any bland fixed oilsuch as a synthetic mono- or di-glyceride may be employed. Fatty acidssuch as oleic acid and its glyceride derivatives, including olive oiland castor oil, especially in their polyoxyethylated versions, areuseful in the preparation of injectables. These oil solutions orsuspensions may also contain long-chain alcohol diluents or dispersants.

Additionally, the compounds may be administered orally in the form ofcapsules, tablets, aqueous suspensions, or solutions. Tablets maycontain carriers such as lactose and corn starch, and/or lubricatingagents such as magnesium stearate. Capsules may contain diluentsincluding lactose and dried corn starch. Aqueous suspensions may containemulsifying and suspending agents combined with the active ingredient.The oral dosage forms may further contain sweetening, flavoring,coloring agents, or combinations thereof.

The compounds may also be administered rectally in the form ofsuppositories. These compositions can be prepared by mixing the drugwith a suitable non-irritating excipient which is solid at roomtemperature, but liquid at rectal temperature and, therefore, will meltin the rectum to release the drug. Such materials include cocoa butter,beeswax, and polyethylene glycols.

Furthermore, the compounds may be administered topically, especiallywhen the conditions addressed for treatment involve areas or organsreadily accessible by topical application, including neurologicaldisorders of the eye, the skin, or the lower intestinal tract. Suitabletopical formulations can be readily prepared for each of these areas.

For topical application to the eye, or ophthalmic use, the compounds canbe formulated as micronized suspensions in isotonic, pH adjusted sterilesaline, or, preferably, as a solution in isotonic, pH adjusted sterilesaline, either with or without a preservative such as benzylalkoniumchloride. Alternatively, the compounds may be formulated into ointments,such as petrolatum, for ophthalmic use.

For topical application to the skin, the compounds can be formulatedinto suitable ointments containing the compounds suspended or dissolvedin, for example, mixtures with one or more of the following: mineraloil, liquid petrolatum, white petrolatum, propylene glycol,polyoxyethylene polyoxypropylene compound, emulsifying wax, and water.Alternatively, the compounds can be formulated into suitable lotions orcreams containing the active compound suspended or dissolved in, forexample, a mixture of one or more of the following: mineral oil,sorbitan monostearate, polysorbate 60, cetyl ester wax, cetearylalcohol, 2-octyldodecanol, benzyl alcohol, and water.

Topical application to the lower intestinal tract can be effected in arectal suppository formulations (see above) or in suitable enemaformulations.

Dosage levels on the order of about 0.1 mg to about 10,000 mg of theactive ingredient compound are useful in the treatment of the aboveconditions, with preferred levels of about 0.1 mg to about 1,000 mg. Theamount of active ingredient that may be combined with the carriermaterials to produce a single dosage form will vary depending upon thehost treated and the particular mode of administration.

It is understood, however, that a specific dose level for any particularpatient will depend upon a variety of factors, including the activity ofthe specific compound employed; the age, body weight, general health,sex and diet of the patient; the time of administration; the rate ofexcretion; drug combination; the severity of the particular diseasebeing treated; and the form of administration.

As neurotrophic agents, the compounds can be administered with otherneurotrophic agents such as neurotrophic growth factor, brain derivedgrowth factor, glial derived growth factor, cilial neurotrophic factor,insulin growth factor and active truncated derivatives thereof, acidicfibroblast growth factor, basic fibroblast growth factor,platelet-derived growth factors, neurotropin-3, and neurotropin 4/5. Thedosage level of other neurotrophic drugs will depend upon the factorspreviously stated and the neurotrophic effectiveness of the drugcombination.

The neurotrophic compounds of this invention can be periodicallyadministered to a patient undergoing treatment for neurologicaldisorders or for other reasons in which it is desirable to stimulateneuronal regeneration and growth, such as in various peripheralneuropathic and neurological disorders relating to neurodegeneration.The compounds of this invention can also be administered to mammalsother than humans for treatment of various mammalian neurologicaldisorders.

Pharmaceutical Compositions of the Invention

The present invention also relates to a pharmaceutical compositioncomprising:

-   -   (i) an effective amount of a compound of the present invention;        and    -   (ii) a pharmaceutically acceptable carrier.

In a preferred embodiment, such pharmaceutical composition is effectivefor effecting a neuronal activity, for treating neurodegenerativediseases, neurological disorders, and nerve damage, or for promotingnerve growth in an animal.

The above discussion relating to the utility and administration of thecompounds of the present invention also applies to the pharmaceuticalcompositions of the present invention.

EXAMPLES

The following examples are illustrative of the present invention and arenot intended to be limitations thereon. Unless otherwise specified, allpercentages are based on 100% by weight of the final compound.

Example 1 Synthesis of(2S)-2-({1-oxo-5-phenyl}-pentyl-1-(3,3-dimethyl-1,2-dioxopentyl)pyrrolidine(1)

(2S)-2-(1-oxo-5-phenyl)pentyl-N-benzylpyrrolidine.1-chloro-4-phenylbutane (1.78 g; 10.5 mmol) in 20 mL of THF was added to0.24 g (10 mmol) of magnesium turnings in 50 mL of refluxing THF. Afterthe addition was complete, the mixture was refluxed for an additional 5hours, and then added slowly to a refluxing solution ofN-benzyl-L-proline ethyl ester (2.30 g (10 mmol) in 100 mL of THF. After2 hours of further reflux, the mixture was cooled and treated with 5 mLof 2 N HCl. The reaction mixture was diluted with ether (100 mL) andwashed with saturated NaHCO₃, water and brine. The organic phase wasdried, concentrated and chromatographed, eluting with 5:1 CH₂Cl₂:EtOActo obtain 2.05 g (64%) of the ketone as an oil, ¹H NMR (CDCl₃; 300 MHz):1.49-2.18 (m, 8H); 2.32-2.46 (m, 1H); 2.56-2.65 (m, 2H); 2.97-3.06 (m,1H); 3.17-3.34 (m, 1H); 3.44-3.62 (m, 1H); 4.02-4.23 (m; 2H); 7.01-7.44(m, 10H).

(2S)-2-(1-oxo-5-phenyl)pentylpyrrolidine. The ketone compound (500 mg)and palladium hydroxide (20% on carbon, 50 mg) was hydrogenated at 40psi in a Paar shaker overnight. The catalyst was removed by filtrationand the solvent was removed in vacuo. The free amine was obtained as ayellow oil (230 mg; 100%), ¹H NMR (CDCl₃; 300 MHz): 1.75-2.34 (m, 10H);2.55 (m, 2H); 2.95 (dm, 1H); 3.45-3.95 (m, 1H); 4.05 (m, 1H); 7.37 (m,5H).

(2S)-2-(1-oxo-5-phenyl)pentyl-1-(1,2-dioxo-2-methoxyethyl)pyrrolidine.To a solution of (2S)-2-(1-oxo-4-phenyl)butylpyrrolidine (230 mg; 1.0mmol) in CH₂Cl₂ (20 mL) at 0° C. was added dropwise methyloxalylchloride (135 mg; 1.1 mmol). After stirring at 0° C. for 3 hours, thereaction was quenched with saturated NH₄Cl and the organic phase waswashed with water and brine and dried and concentrated. The cruderesidue was purified on a silica gel column, eluting with 20:1CH₂Cl₂:EtOAc to obtain 300 mg of the oxamate as a clear oil (98%), ¹HNMR (CDCl₃; 300 MHz): 1.68 (m, 4H); 1.91-2.38 (m, 4H); 2.64 (t, 2H);3.66-3.80 (m, 2H); 3.77, 3.85 (s, 3H total); 4.16 (m, 2H); 4.90 (m, 1H);7.16 (m, 3H); 7.27 (m, 2H).

(2S)-2-({1-oxo-5-phenyl}-pentyl-1-(3,3-dimethyl-1,2-dioxopentyl)pyrrolidine(1). To a solution of the oxamate above (250 mg; 0.79 mmol) in anhydrousether (15 mL), cooled to −78° C., was added 1,1-dimethylpropylmagnesiumchloride (0.8 mL of a 1.0 M solution in ether; 0.8 mmol). After stirringthe resulting mixture at −78° C. for 2 hours, the reaction was quenchedby the addition of 2 mL of saturated NH₄Cl, followed by 100 mL of EtOAc.The organic phase was washed with brine, dried, concentrated, andpurified on a silica gel column, eluting with 50:1 CH₂Cl₂:EtOAc.Compound 1 was obtained as a clear oil, 120 mg, ¹H NMR (CDCl₃, 300 MHz)δ 0.87 (t, 3H, J=7.5); 1.22 (s, 3H); 1.25 (s, 3H); 1.67 (m, 4H);1.70-2.33 (m, 6H); 2.61 (t, 2H, J=7.1); 3.52 (m, 2H); 4.17 (t, 2H,J=6.2); 4.52 (m, 1H); 7.16-7.49 (m, 5H). Anal. Calcd. for C₂₂H₃₁NO₃—H₂O:C, 70.37; H, 8.86; N, 3.73. Found: 70.48; H, 8.35; N, 3.69.

Example 2 Synthesis of 2-({1-Oxo-4-phenyl}hexyl)(2S)-1-(3,3-dimethyl-1,2-dioxopentyl)piperidine (17)

The method of Example 1 was utilized to prepare2-({1-oxo-6-phenyl}hexyl)(2S)-1-(3,3-dimethyl-1,2-dioxopentyl)piperidine (17), utilizing2-(ethoxy carboxylate)N-benzylpiperidine and 1-chloro-5-phenyl pentaneas the starting materials.

Example 3 Synthesis of2-(1-Oxo-4-phenyl)butyl-1-(3,3-dimethyl-1,2-dioxobutyl)pyrrolidine (63)

The method of Example 1 was utilized to prepare2-(1-Oxo-4-phenyl)butyl-1-(3,3-dimethyl-1,2-dioxobutyl)pyrrolidine (63),utilizing 1-chloro-4-(4-hydroxyphenyl)butane, for1-chloro-4-phenylbutane, as a starting material.

Example 4 Synthesis of(2S)-3,3-dimethyl-1-[2-(5-(3-pyridyl)pyrrolidinyl]pentane-1,2-dione (2)

Tert-butyl 2-pent-4-enoylpyrrolidinecarboxylate. To a solution of3-butenylmagnesiumbromide (97 ml of a 0.5 M solution; 48.4 mmol) in THF(15 ml), cooled to 0° C. and under a nitrogen atmosphere, was addeddropwise with stirring a solution of tert-butyl2-(N-methoxy-N-methylcarbamoyl)pyrrolidine carboxylate (5.0 g, 19.4mmol) in 15 ml of THF. The mixture was stirred overnight while slowlycoming to room temperature. The reaction was quenched by the addition of80 ml saturated NH₄Cl followed by 50 ml of ethyl acetate and 20 ml ofwater. The layers were separated, and the aqueous layer was extractedwith 2×100 ml ethyl acetate. The combined organic layers were dried overMgSO₄, filtered, concentrated, and the crude product was purified on asilica gel column with 10% ethyl acetate in hexane to obtain the olefintert-butyl 2-pent-4-enoylpyrrolidine carboxylate as a clear oil, 4.30 g(88%): ¹H NMR (CDCl₃, 400 MHz): d.

Methyl 2-oxo-2-(2-pent-4-enoylpyrrolidinyl)acetate. Trifluoroacetic acid(“TFA”; 65.7 g; 576 mmol) was added dropwise to a solution of 24.3 g (96mmol) of tert-butyl (2-pent-4-enoyl)pyrrolidinecarboxylate in 45 ml ofCH₂Cl₂, cooled to 0° C. After stirring for 4 hours, Thin LayerChromatography (“TLC”) indicated that the reaction was complete, and themixture was concentrated in vacuo to remove TFA. The residue wasdissolved in 800 ml of CH₂Cl₂ and treated with 2 equivalents oftriethylamine while stirring and cooling the mixture in an ice bath.Methyl oxalyl chloride (13.5 g; 106 mmol) was added as a solution in 40ml CH₂Cl₂, in 10 ml portions each followed by 5 ml of Et₃N. After theaddition, a final 10 ml portion of Et₃N was added and the mixture wasstirred overnight. It was concentrated, treated with 100 ml of 1:1 ethylacetate/hexane), filtered to remove solids, and the concentrated residuepurified by SGC, eluting with 1:1 hexane/ethyl acetate, to obtain theoxamate methyl 2-oxo-2-(2-pent-4-enoylpyrrolidinyl)acetate as a brownishoil, 18.80 g (82%). ¹H NMR (CDCl₃, 400 MHz): d.

3,3-Dimethyl-1-(2-pent-4-enoylpyrrolidinyl)pentane-1,2-dione. A solutionof methyl 2-oxo-2-(2-pent-4-enoylpyrrolidinyl)acetate (21.0 g; 88 mmol)in 150 ml THF was cooled to −78° C., under nitrogen, and treated with200 ml (180 mmol) of 0.9 M 3,3-dimethylpropyl magnesium chloride. Afterstirring for 2.5 hours, TLC indicated that the reaction was complete. Itwas quenched with 300 ml of saturated NH₄Cl followed by 200 ml of ethylacetate. The layers were separated and the aqueous layer was extractedonce more with 300 ml of ethyl acetate. The combined organic layers weredried over MgSO₄, filtered, concentrated, and the product purified onsilica gel with 20% ethyl acetate in hexane, to obtain3,3-dimethyl-1-(2-pent-4-enoylpyrrolidinyl)pentane-1,2-dione as a lightyellow oil, 21.0 g (85%).

3,3-Dimethyl-1-[2-(5-(3-pyridyl)pent-4-enoyl)pyrrolidinyl]pentane-1,2-dione.To a solution of olefin3,3-dimethyl-1-(2-pent-4-enoylpyrrolidinyl)pentane-1,2-dione (500 mg;1.78 mmol) in 7 ml of Et₃N was added 3-bromopyridine (310 mg; 1.96mmol), palladium (II) acetate (20 mg; 0.09 mmol), andtri-(orthotolyl)phosphine (108 mg; 0.36 mmol), and the mixture wasrefluxed overnight. The mixture was concentrated and the productspurified on a silica gel column, eluting with a gradient from 50% ethylacetate in hexane to 75% ethyl acetate. Two products were obtained aslight yellow oils. The major product (85% of the mixture) was theproduct of aryl coupling to the terminus of the C—C double bond,3,3-dimethyl-1-[2-(5-(3-pyridyl)pent-4-enoyl)pyrrolidinyl]pentane-1,2-dione;the minor product was the product of coupling at the more substitutedcarbon. The overall yield of the desired product was 480 mg (75%).

3,3-Dimethyl-1-[2-(5-(3-pyridyl)pentanoyl)pyrrolidinyl]pentane-1,2-dione(2). Platinum oxide (12 mg) was added to a solution of3,3-dimethyl-1-[2-(5-(3-pyridyl)pent-4-enoyl)pyrrolidinyl]pentane-1,2-dione (300 mg; 0.84 mmol) in methanol. (8 ml).The mixture was hydrogenated at 1 atm. for 2.5 hours. TLC indicated thatthe reaction was complete, and it was filtered through Celite andconcentrated. Eluting through a plug of silica gel (ethyl acetate)furnished analytically pure material, 260 mg (87%). ¹H NMR (CDCl₃, 400MHz): δ 0.87 (t, 3H, J=7.5); 1.21 (s, 6H); 1.64 (m, 4H); 1.69 (m, 2H);1.78 (m, 1H); 1.96 (m, 2H); 2.15 (m, 1H); 2.53 (m, 1H); 2.63 (m, 2H);3.49 (m, 1H); 3.53 (m, 1H); 4.57 (dd, 1H, J=8.8, 4.8); 7.20 (m, 1H);7.49 (m, 1H, J=7.8); 8.44 (m, 2H). Anal. Calcd. for C₂₁H₃₀N₂O₃: C,70.36; H, 8.44; N, 7.81. Found: C, 70.15; H, 8.54; N, 7.76. TLC: R₁=0.80(ethyl acetate:ethanol 4:1). Note: this final hydrogenation step may bedone using 10% Pd/C, and hydrogenating for 5 hours at 60 psi. Ethanol orethyl acetate may be used instead of methanol.

Example 5 Synthesis of(2S)-3,3-dimethyl-1-[2-(5-(4-hydroxyphenyl)pentanoyl)pyrrolidinyl]pentane-1,2-dione(68)

The method of Example 4 was utilized to prepare3,3-dimethyl-1-(2-pent-4-enoylpyrrolidinyl)pentane-1,2-dione.

3,3-Dimethyl-1-(2-{5-[4-(phenylmethoxy)phenyl]pent-4-enoyl}pyrrolidinyl)pentane-1,2-dione.A solution of3,3-dimethyl-1-(2-pent-4-enoylpyrrolidinyl)pentane-1,2-dione (1.73 g;6.20 mmol), 4-benzyloxybromobenzene (1.80 g; 6.83 mmol), palladium (II)acetate (70 mg; 0.31 mmol), and tri(orthotolyl)phosphine (380 mg; 1.24mmol) in triethylamine (23 ml) was refluxed overnight. The mixture wasconcentrated in vacuo and purified on a silica gel column, eluting witha gradient from 10% ethyl acetate/hexane to 20% ethyl acetate/hexane, toobtain 1.72 g (60%) of3,3-dimethyl-1-(2-{5-[4-(phenylmethoxy)phenyl]pent-4-enoyl}pyrrolidinyl)pentane-1,2-dioneas a yellow oil.

1-{2-[5-(4-Hydroxyphenyl)pentanoyl]pyrrolidinyl}-3,3-dimethylpentane-1,2-dione(68). A mixture of 1.63 g (3.53 mmol) of3,3-dimethyl-1-(2-{5-[4-(phenylmethoxy)phenyl]pent-4-enoyl}pyrrolidinyl)pentane-1,2-dioneand 400 mg of 10% Pd/C in 100 ml of ethyl acetate was hydrogenated at 50psi overnight. The mixture was filtered through Celite, concentrated,and chromatographed (25% ethyl acetate/hexane) to obtain 800 mg (61%) of1-{2-[(5-(4-hydroxyphenyl)pentanoyl]pyrrolidinyl}-3,3-dimethylpentane-1,2-dione(68). ¹H NMR (CDCl₃, 400 MHz): δ 0.87 (t, 3H, J=7.50); 1.21 (s, 6H) 1.63(m, 4H); 1.67 (m, 2H); 1.93 (m, 3H); 2.04 (m, 1H) 2.52 (m, 4H); 3.47 (m,2H); 4.57 (m, 1H); 6.72 (d, 2H, J=8.40); 7.03 (d, 2H, J=8.40). Anal.Calcd. for C₂₂H₃₁NO₄: C, 70.75; H, 8.37; N, 3.75. Found: C, 70.64; H,8.44; N, 3.65. TLC: R_(f)=0.45 (25% ethyl acetate/hexane).

Example 6 Synthesis of 2-phenyl-1-ethyl1-(3,3-dimethyl-1,2-dioxopentyl)-2-piperidinecarbothioate (10)

Methyl(2S)-1-(1,2-dioxo-2-methoxyethyl)-2-pyrrolidinecarboxylate. Asolution of L-proline methyl ester hydrochloride (3.08 g; 18.60 mmol) indry methylene chloride was cooled to 0° C. and treated withtriethylamine (3.92 g; 38.74 mmol; 2.1 eq). After stirring the formedslurry under a nitrogen atmosphere for 15 min, a solution of methyloxalyl chloride (3.20 g; 26.12 mmol) in methylene chloride (45 ml) wasadded dropwise. The resulting mixture was stirred at 0° C. for 1.5 hour.After filtering to remove solids, the organic phase was washed withwater, dried over MgSO₄ and concentrated. The crude residue was purifiedon a silica gel column, eluting with 50% ethyl acetate in hexane, toobtain 3.52 g (88%) of the product as a reddish oil. Mixture ofcis-trans amide rotamers; data for trans rotamer given. ¹H NMR (CDCl₃):δ 1.93 (dm, 2H); 2.17 (m, 2H); 3.62 (m, 2H); 3.71 (s, 3H); 3.79, 3.84(s, 3H total); 4.86 (dd, 1H, J=8.4, 3.3).

Methyl(2S)-1-(1,2-dioxo-3,3-dimethylpentyl)-2-pyrrolidinecarboxylate. Asolution of methyl(2S)-1-(1,2-dioxo-2-methoxyethyl)-2-pyrrolidinecarboxylate (2.35 g;10.90 mmol) in 30 ml of tetrahydrofuran (THF) was cooled to −78° C. andtreated with 14.2 ml of a 1.0 M solution of 1,1-dimethylpropylmagnesiumchloride in THF. After stirring the resulting homogeneous mixture at−78° C. for three hours, the mixture was poured into saturated ammoniumchloride (100 ml) and extracted into ethyl acetate. The organic phasewas washed with water, dried, and concentrated, and the crude materialobtained upon removal of the solvent was purified on a silica gelcolumn, eluting with 25% ethyl acetate in hexane, to obtain 2.10 g (75%)of the oxamate as a colorless oil, ¹H NMR (CDCl₃): δ 0.88 (t, 3H); 1.22,1.26 (s, 3H each); 1.75 (dm, 2H); 1.87-2.10 (m, 3H); 2.23 (m, 1H); 3.54(m, 2H); 3.76 (s, 3H); 4.52 (dm, 1H, J=8.4, 3.4).

(2S)-1-(1,2-dioxo-3,3-dimethylpentyl)-2-pyrrolidine-carboxylic acid. Amixture of methyl(2S)-1-(1,2-dioxo-3,3-dimethylpentyl)-2-pyrrolidinecarboxylate (2.10 g;8.23 mmol), 1 N LiOH (15 ml), and methanol (50 ml) was stirred at 0° C.for 30 minutes and at room temperature overnight. The mixture wasacidified to pH 1 with 1 N HCl, diluted with water, and extracted into100 ml of methylene chloride. The organic extract was washed with brineand concentrated to deliver 1.73 g (87%) of snow-white solid which didnot require further purification, ¹H NMR (CDCl₃): δ 0.87 (t, 3H); 1.22,1.25 (s, 3H each); 1.77 (dm, 2H); 2.02 (m, 2H); 2.17 (m, 1H); 2.25 (m,1H); 3.53 (dd, 2H, J=10.4, 7.3); 4.55 (dd, 1H, J=8.6, 4.1).

2-phenyl-1-ethyl1-(3,3-dimethyl-1,2-dioxopentyl)-2-piperidinecarbothioate (10). To asolution of(2S)-1-(1,2-dioxo-3,3-dimethylpentyl)-2-pyrrolidinecarboxylic acid (241mg; 1.0 mmol) in CH₂Cl₂ (10 ml) was added dicyclohexylcarbodiimide (226mg; 1.1 mmol). After stirring the resulting mixture for 5 minutes, thesolution was cooled to 0° C. and treated with a solution of phenylmercaptan (138 mg; 1.0 mmol) and 4-dimethylaminopyridine (6 mg) in 5 mlof CH₂Cl₂. The mixture was allowed to warm to room temperature withstirring overnight. The solids were removed by filtration and thefiltrate was concentrated in vacuo; the crude residue was purified byflash chromatography (10:1 hexane:EtOAc) to obtain 302 mg (84%) of 10 asan oil, ¹H NMR (CDCl₃, 300 MHZ): δ 0.85 (t, 3H, J=7.5); 1.29 (s, 3H);1.31 (s, 3H); 1.70-2.32 (m, 6H); 2.92 (t, 2H, J=7.4); 3.22 (t, 2H,J=7.4); 3.58 (m, 2H); 4.72 (m, 1H); 7.23-7.34 (m, 5H). Anal. Calcd. forC₂₀H₂₇NO₃S—0.4H₂O: C, 65.15; H, 7.60; N, 3.80. Found: C, 65.41; H, 7.49;N, 3.72.

Example 7 Synthesis of 2-phenyl-1-ethyl(2S)-1-(3,3-dimethyl-1,2-dioxopentyl)-2-pyrrolidinecarbothioate (9)

Methyl 1-(1,2-dioxo-2-methoxyethyl)-2-piperidinecarboxylate. A solutionof methyl pipecolate hydrochloride (8.50 g; 47.31 mmol) in dry methylenechloride (100 ml) was cooled to 0° C. and treated with triethylamine(10.5 g; 103 mmol; 2.1 eq). After stirring the formed slurry under anitrogen atmosphere for 15 minutes, a solution of methyl oxalyl chloride(8.50 g; 69.4 mmol) in methylene chloride (75 ml) was added dropwise.The resulting mixture was stirred at 0° C. for 1.5 hours. Afterfiltering to remove solids, the organic phase was washed with water,dried over MgSO₄ and concentrated. The crude residue was purified on asilica gel column, eluting with 50% ethyl acetate in hexane, to obtain9.34 g (86%) of the product as a reddish oil. Mixture of cis-trans amiderotamers; data for trans rotamer given. ¹H NMR (CDCl₃): δ 1.22-1.45 (m,2H); 1.67-1.78 (m, 3H); 2.29 (m, 1H); 3.33 (m, 1H); 3.55 (m, 1H); 3.76(s, 3H); 3.85, 3.87 (s, 3H total); 4.52 (dd, 1H).

Methyl 1-(1,2-dioxo-3,3-dimethylpentyl)-2-piperidine-carboxylate. Asolution of methyl 1-(1,2-dioxo-2-methoxyethyl)-2-piperidinecarboxylate(3.80 g; 16.57 mmol) in 75 ml of tetrahydrofuran (THF) was cooled to−78° C. and treated with 20.7 ml of a 1.0 M solution of1,1-dimethyl-propylmagnesium chloride in THF. After stirring theresulting-homogeneous mixture at −78° C. for three hours, the mixturewas poured into saturated ammonium chloride (100 ml) and extracted intoethyl acetate. The organic phase was washed with water, dried, andconcentrated, and the crude material obtained upon removal of thesolvent was purified on a silica gel column, eluting with 25% ethylacetate in hexane, to obtain 3.32 g (74%) of the oxamate as a colorlessoil, ¹NMR (CDCl₃): δ 0.88 (t, 3H); 1.21, 1.25 (s, 3H each); 1.35-1.80(m, 7H); 2.35 (m, 1H); 3.24 (m, 1H); 3.41 (m, 1H); 3.76 (s, 3H); 5.32(d, 1H).

1-(1,2-dioxo-3,3-dimethylpentyl)-2-piperidine-carboxylic acid. A mixtureof methyl 1-(1,2-dioxo-3,3-dimethylpentyl)-2-piperidinecarboxylate (3.30g; 12.25 mmol), 1 N LiOH (15 ml), and methanol (60 ml) was stirred at 0°C. for 30 minutes and at room temperature overnight. The mixture wasacidified to pH 1 with 1 N HCl, diluted with water, and extracted into100 ml of methylene chloride. The organic extract was washed with brineand concentrated to deliver 2.80 g (87%) of snow-white solid which didnot require further purification, ¹H NMR (CDCl₃): δ 0.89 (t, 3H); 1.21,1.24 (s, 3H each); 1.42-1.85 (m, 7H); 2.35 (m, 1H); 3.22 (d, 1H); 3.42(m, 1H); 5.31 (d, 1H)

2-phenyl-1-ethyl(2S)-1-(3,3-dimethyl-1,2-dioxopentyl)-2-pyrrolidinecarbothioate (9). Toa solution of 1-(1,2-dioxo-3,3-dimethylpentyl)-2-piperidine-carboxylicacid (255 mg; 1.0 mmol) in CH₂Cl₂ (10 ml) was addeddicyclohexylcarbodiimide (226 mg; 1.1 mmol). After stirring theresulting mixture for 5 minutes, the solution was cooled to 0° C. andtreated with a solution of phenyl mercaptan (138 mg; 1.0 mmol) and4-dimethylaminopyridine (6 mg) in 5 ml of CH₂Cl₂. The mixture wasallowed to warm to room temperature with stirring overnight. The solidswere removed by filtration and the filtrate was concentrated in vacuo;the crude residue was purified by flash chromatography (10:1hexane:EtOAc) to obtain 300 mg (80%) of 9 as an oil, ¹H NMR (CDCl₃, 300MHZ): d 0.94 (t, 3H, J=7.5); 1.27 (s, 3H); 1.30 (s, 3H); 1.34-1.88 (m,7H); 2.45 (m, 1H); 2.90 (t, 2H, J=7.7); 3.26 (t, 2H, J=7.7); 3.27 (m,1H); 3.38 (m, 1H); 5.34 (m, 1H); 7.24-7.3.6 (m, 5H). Anal. Calcd. forC₂₁H₂₉NO₃S: C, 67.17; H, 7.78; N, 3.73. Found: C, 67.02; H, 7.83; N,3.78.

Example 8

A patient is suffering from a condition or disorder requiringstimulation of damaged neurons, promotion of neuronal regeneration,prevention of neurodegeneration, or treatment of a neurologicaldisorder; wherein the neurological disorder is selected from the groupconsisting of peripheral neuropathy caused by physical injury or diseasestate, traumatic injury to the brain, physical damage to the spinalcord, stroke associated with brain damage, and neurological disordersrelating to neurodegeneration; and wherein the neurological disorderrelating to neurodegeneration is selected from the group consisting ofAlzheimer's Disease, Huntington's Disease, Parkinson's Disease, andamyotrophic lateral sclerosis.(2S)-3,3-dimethyl-1-[2-(5-(3-pyridyl)pyrrolidinyl]pentane-1,2-dione,2-(1-Oxo-4-phenyl)-butyl-1-(3,3-dimethyl-1,2-dioxobutyl)pyrrolidine,(2S)-3,3-dimethyl-1-[2-(5-(4-hydroxyphenyl)pentanoyl)pyrrolidinyl]pentane-1,2-dione,or 2-({1-oxo-6-phenyl}-hexyl)(2S)-1-(3,3-dimethyl-1,2-dioxopentyl)piperidine, or a pharmaceuticalcomposition comprising the same, may be administered to the patient.Protection from or recovery from the effects of the describedcondition(s) or disorder(s) is expected to occur following treatment.

The compounds of the present invention have an affinity for the FK506binding protein, particularly FKBP12. The inhibition of the prolylpeptidyl cis-trans isomerase activity of FKBP may be measured as anindicator of this affinity and as a possible indicator of neurotrophicactivity.

K_(i) Test Procedure

Inhibition of the peptidyl-prolyl isomerase (rotamase) activity of theinventive compounds can be evaluated by known methods described in theliterature (Harding et al., Nature, 1989, 341:758-760; Holt et al. J.Am. Chem. Soc., 115:9923-9938). These values are obtained as apparentK_(i)′S, and are presented for representative compounds in Table IV. Thecis-trans isomerization of an alanine-proline bond in a model substrate,N-succinyl-Ala-Ala-Pro-Phe-p-nitroanilide, is monitoredspectrophotometrically in a chymotrypsin-coupled assay, which releasespara-nitroanilide from the trans form of the substrate. The inhibitionof this reaction caused by the addition of different concentrations ofinhibitor is determined, and the data is analyzed as a change infirst-order rate constant as a function of inhibitor concentration toyield the apparent K_(i) values.

In a plastic cuvette are added 950 ml of ice cold assay buffer (25 mMHEPES, pH 7.8, 100 mM NaCl), 10 ml of FKBP (2.5 mM in 10 mM Tris-Cl pH7.5, 100 mM NaCl, 1 mM dithiothreitol), 25 ml of chymotrypsin (50 mg/mlin 1 mm HCl) and 10 ml of test compound at various concentrations indimethyl sulfoxide. The reaction is initiated by the addition of 5 ml ofsubstrate (succinyl-Ala-Phe-Pro-Phe-para-nitroanilide, 5 mg/ml in 2.35mM LiCl in trifluoroethanol).

The absorbance at 390 nm versus time is monitored for 90 seconds using aspectrophotometer and the rate constants are determined from theabsorbance versus time data files.

The data for these experiments for representative compounds arepresented in Table IV under the column “Ki”.

The neurotrophic effects of the compounds of the present invention canbe demonstrated in cellular biological experiments in vitro, asdescribed below.

Chick Dorsal Root Ganglion Cultures and Neurite Outgrowth

The neurotrophic effects of the FKBP inhibitor compounds weredemonstrated by evaluating the ability of the compounds to promoteneurite outgrowth in cultured chick sensory neurons from dorsal rootganglia. Dorsal root ganglia were dissected from chick embryos of tenday gestation. Whole ganglion explants were cultured on thin layerMatrigel-coated 12 well plates with Liebovitz L15 plus high glucosemedia supplemented with 2 mM glutamine and 10% fetal calf serum, andalso containing 10 μm cytosine β-D arabinofuranoside (Ara C) at 37° C.in an environment containing 5% CO₂. Twenty-four hours later, the DRGswere treated with various concentrations of nerve growth factor,immunophilin ligands or combinations of NFG plus drugs. Forty-eighthours after drug treatment, the ganglia were visualized under phasecontrast or Hoffman Modulation contrast with a Zeiss Axiovert invertedmicroscope. Photomicrographs of the explants were made, and neuriteoutgrowth was quantitated. Neurites longer than the ORG diameter werecounted as positive, with total number of neurites quantitated per eachexperimental condition. Three to four DRGs are cultured per well, andeach treatment was performed in duplicate.

Dose-response curves were generated from which ED₅₀ values wereobtained. The results of these experiments are presented in Table IVunder the column “ED50”. Representative photomicrographs of untreated(control) sensory neurons and of sensory neurons treated with compound 1(10 pM, 1 nM, 1 μM), and related compounds 2-Phenyl-1-ethyl(2S)-1-(3,3-dimethyl-1,2-dioxopentyl)-2-pyrrolidinecarbothioate (10 pM,1 nM, 100 nM) and 2-Phenyl-1-ethyl1-(3,3-dimethyl-1,2-dioxopentyl)-2-piperidinecarbothioate (10 pM, 1 nM,100 nM) promoting neurite outgrowth in sensory neurons are shown inFIGS. 1(A-D), 2(A-D), and 3(A-D), respectively.

MPTP Model of Parkinson's Disease

The remarkable neurotrophic and neuroregenerative effects of the presentinventive compounds were further demonstrated in an animal model ofneurodegenerative disease. MPTP lesioning of dopaminergic neurons inmice was used as an animal model of Parkinson's Disease. Four week oldmale CD1 white mice were dosed i.p. with 30 mg/kg of MPTP for 5 days.Test compounds (4 mg/kg), or vehicle, were administered s.c. along withthe MPTP for 5 days, as well as for an additional 5 days followingcessation of MPTP treatment. At 18 days following MPTP treatment, theanimals were sacrificed and the striata were dissected and homogenized.Immunostaining was performed on saggital and coronal brain sectionsusing anti-tyrosine hydroxylase 1 g to quantitate survival and recoveryof dopaminergic neurons. In animals treated with MPTP and vehicle, asubstantial loss of functional dopaminergic terminals was observed ascompared to non-lesioned animals. Lesioned animals receiving testcompounds showed a significant recovery of TH-stained dopaminergicneurons.

The results of these experiments are presented in TABLE IV under thecolumn “% TH recovery”. Quantitation for the recovery of TH-positivedopaminergic neurons in the striatum of animals receiving compounds ofthe invention, including compound 1, and for representative control andlesioned animals not receiving the test drugs, are presented in FIG. 4.

TABLE IV In Vitro Test Results Compound Ki, nM ED50, nM % TH recovery 131 0.4 23 2 210 — — 3 85 — — 9 104 0.5 61 10 12 0.8 54 11 299 0.36 53 12442 0.025 — 14 313 0.9 48 28 362 — 52 29 1698 — — 30 34 0.9 48 31 62 — —32 7 — 56 33 68 — — 34 8.9 0.011 37.32 35 347 — — 36 1226 — — 37 366 — —38 28 — — 39 259 — — 40 188 — 25 41 31 — — 42 757 — — 43 21 — 50 44 127— 28 45 1334 — — 46 55 — 62 47 33 — — 48 6 — — 49 261 — — 50 37 — — 5130 — — 52 880 — — 53 57 — — 54 79 — — 55 962 — — 56 90 — — 57 139 — — 58196 — — 59 82 — — 60 163 — — 61 68 — — 62 306 5 38 63 177 — — 64 284 — —65 49 — 23 66 457 — 25 67 788 — —

All publications and patents identified above are hereby incorporated byreference.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention and all suchmodifications are intended to be included within the scope of thefollowing claims.

1. A compound of the formula

wherein C is S; Z is CH₂ or S; R₃ is 2-phenylpropyl or 3-phenylpropyl;and R₄ is 1,1-Dimethylpropyl, having an affinity for FKBP-typeimmunophilin.
 2. The compound of claim 1, wherein the FKBP-typeimmunophilin is FKBP-12.
 3. A pharmaceutical composition comprising: (i)a compound of the formula

wherein C is S; Z is CH₂ or S; R₃ is 2-phenylpropyl or 3-phenylpropyl;and R₄ is 1,1-Dimethylpropyl, having an affinity for FKBP-typeimmunophilin; and (ii) a pharmaceutically acceptable carrier.
 4. Thepharmaceutical composition of claim 3, wherein the FKBP-typeimmunophilin is FKBP-12.
 5. A method of promoting neuronal growth andregeneration, comprising administering to an animal in need thereof atherapeutically effective amount of a compound of the formula

wherein C is S; Z is CH₂ or S; R₃ is 2-phenylpropyl or 3-phenylpropyl;and R₄ is 1,1-Dimethylpropyl, having an affinity for FKBP-typeimmunophilin.
 6. The method of claim 5, wherein the promoting neuronalgrowth is stimulation of damaged neurons, promotion of neuronalregeneration, or treatment of a neurological disorder.
 7. The method ofclaim 6, wherein the neurological disorder is peripheral neuropathycaused by physical injury or disease state, traumatic injury to thebrain, physical damage to the spinal cord, stroke associated with braindamage, or neurological disorder relating to neurodegeneration.
 8. Themethod of claim 7, wherein the neurological disorder relating toneurodegeneration is Alzheimer's disease, Huntington's disease,Parkinson's disease or amyotrophic lateral sclerosis.
 9. The method ofclaim 5, wherein the FKBP-type immunophilin is FKBP-12.